New Reagents for Photoaffinity Labeling: Synthesis and Photolysis of Functionalized Perfluorophenyl Azides

Article abstract of DOI:10.1021/jo00298a048

Functionalized perfluorophenyl azides (PFPA) 2-6, 8-12, 14-19, and 21-29 were synthesized, allowing the attachment of PFPA to other molecules for application as photolabels.Two biactive molecules were modified by a PFPA as potential photoaffinity labeling reagents.Photolysis of two representative members was investigated.Photolysis of azide 4 in cyclohexane gave 57 percent of CH insertion product.When photolysis was carried out in the presence of diethylamine as a trapping reagent, it gave 65 percent of NH insertion product, and no ring expansion product was found.The nitro azide 19 showed a shoulder absorption in the longer wavelength compared to azide 4.Azide 19 gave less CH insertion and more aniline products compared to azide 4 when photolyzed in toluene, suggesting that the nitro group accelerates intersystem crossing of the singlet nitrene or the singlet excited azide.Collectively, our results demonstrate that the functionalized PFPA investigated are much better in undergoing CH insertion than their nonfluorinated analogues and suggest that they may constitute an improved series of photolabeling reagents.